1. Field of the Invention
The invention relates to a mechanical coin checker used in coin operated machines like washing machines, coin operated gaming machines, automatic ending machines and the like.
2. Description of the Prior Art
A large number of mechanical coin checkers are known in prior art which have in the region of their coin running channel, which joins onto the coin slot, a sensor arrangement which checks whether the coin is genuine and admissible. The sensors check e.g. the dimensions of the coin, and where the mechanical dimensions of the coin to be checked are identical, they have to be distinguished by means of their metallic properties. Magnetic checking arrangements are known for this purpose. To check the dimensions, there are limitations formed by rails or the like which take into account the diameter or the thickness of the coin. The coin channel has for example a lower running rail down which the coin runs, being supported with its upper edge against a rail. If the coin is too small it falls through below the rail and reaches a return channel. A recess is incorporated in the lower running rail in the longitudinal direction, such that a coin which is too thin slips into this recess and then falls into the return channel. However it sometimes happens that the coin becomes stuck in the recess and it has been shown that in this case there has been manipulation from the outside so that when a non-admissible, too thin coin or disc is inserted, which slides into the recess of the running rail, from outside a wire or a strip of cardboard or the like is inserted into the coin channel, with which implement the coin or disc which has become stuck is pushed forward so that it reaches the acceptance channel or the acknowledgement region.
An object of the present invention, is to improve the mechanical coin checker and to make available an additional measure which prevents passing a non-admissible coin into the acknowledgement region. Another object is to prevent one type of manipulation realized pushing a coin in the coin channel from outside by means of a tool into the acceptance channel.
According to the present invention the mechanical coin checker has a coin channel which has a running rail for the coin to run down, in or at which channel checking arrangements are provided to check the properties of coins, having a coin acceptance shaft and a return shaft, disposed below the running rail, to return coins which are not accepted, the running rail having in the running direction of the coin a recess into which coins which are too thin slide and possibly fall into the return shaft, wherein in front of the acceptance shaft a detent pawl is disposed which is rotatably mounted on a flap forming a part of the coin channel, and because a detent wire, pivotable about a portion of its longitudinal axis, co-operates with its one end region with the detent pawl, and with its other, bent end region is disposed below the recess, in such a way that when a coin slips through the recess, the detent wire, as a result of the weight of the coin acting on the bent end region, pivots about the longitudinal axis, and thus the other end of the detent wire comes into contact with the detent pawl and swivels the latter in the direction of the coin channel, whereby an arm engages in the coin channel. Thus the coin channel is blocked towards the acknowledgement region, such that even by manipulation from outside through the coin slot by means of a tool, such as a strip of cardboard or the like, the coin cannot be pushed into the acceptance channel.